But WIMPs of certain masses can collide with atomic nuclei on occasion—and now it appears such collisions might happen more often than previously thought.

"Before we did this work, I thought a WIMP collided with one of your nuclei once in your lifetime," said Katherine Freese, a professor with the Michigan Center for Theoretical Physics at the University of Michigan.

"Turns out it's more likely to be one a minute."

WIMPy Collisions

According to theory, WIMPs were created at the dawn of the universe, just like other forms of matter.

Although WIMPs don't interact much with normal matter, if two of the particles strike each other, they annihilate—all their mass turns into energy.

"As the universe [expanded and] cooled, [WIMPs] spread so far apart they no longer annihilated and just stuck around," said study co-author Christopher Savage, a postdoctoral researcher with the Oskar Klein Centre at Stockholm University in Sweden.

Models suggest that today billions of WIMPs are streaming through Earth and its inhabitants every second.

Some experiments designed to detect WIMPs are based on the expected probability of a WIMP hitting a particular type of material—such as germanium crystals—and the amount of energy that should be released by the collision.

For the new research, Freese and Savage used similar calculations to look at the masses and abundances of certain kinds of WIMPs and estimate how often a particle might interact with nuclei commonly found in people.

"We know how to do these calculations, we'd just never actually done it for something like a human body," Savage said.

The results showed that oxygen and hydrogen atoms were more likely to be struck by WIMPs. And since we're made from large quantities of water, aka H2O, the human body holds lots of potential for WIMP interactions.